You are largely correct, that on many of these shows (Top Chef being just one), very successful chefs with the right combination of skills and personality can use their new-found fame to find investors, and open a restaurant.

And several of them have. Last summer, I met one in a restaurant in Chicago, who was bar-tending to pay personal bills while the construction on his new place was finalized.

The big money is either in becoming a name-recognized chef, or in owning and managing restaurants. (CF Marco Pierre White's book. Although he managed it without being the least bit nice...)